[Cytological map of the terminal points of the asynapsis in the polytene chromosomes of the salivary glands of Drosophila melanogaster].

A cytological map of the terminal points of the asynapsis (TPA) has been composed for X, 2 (L, R) and 3 (L, R) salivary gland polytene chromosomes of the third instar larvae of the wild type outbred line K-1 Drosophila melanogaster. TPA are distributed along the chromosome length unevenly forming "peaks". These peaks, as a rule, are situated in the intercalary heterochromotin. The coincidence of the main peaks with the regions of an increased crossing-over frequency is noticed. The preferential unidirectionless of termination is characteristic of TPA peaks; in the number of cases, the "discrimination" effect of asynapsises of definite lengths takes place. For the third chromosome, the frequency of simultaneous occurrence of asynapsises adjacent to the chromocenter is shown to exceed the frequency of an accidental combination. The centromeric region is not always, presumably, an obligatory board of the asynapsis, and the chromosome in the synapsis prosess can function as continuous.